Thursday, May 20, 2010

Where Do Rats and Mice Go to Die?

I am often asked by worried enquirers "where will the rats and mice killed with poisons go to die?" The worry is they "don't want a bad smell from dead rodents in the house".

Almost all rodenticides are anti-coagulants. An often perpetuated 'old wives tale' is that anti-coagulant poisons like NO Rats and Mice make the rats and mice thirsty and they go outside in search of water and die there. There is a little truth in this, there is a slightly increased likelihood of the rodents dying outside, but in the vast majority of cases they will go to their nest and die there. Often the nest is inside.

However, even if the rats or mice die inside there is little likelihood of a bad smell. Bad smells are only a problem if the rodent dies somewhere very warm and un-ventilated. In 99% of cases there is not a problem. In order to prevent bad smells it is more important to deal with the infestation as the pests will be dying of natural causes and there is a higher chance of a bad smell. Rodenticide baits are the most efficient and effective way to deal with rat and mouse infestations.

I suggest to worried enquirers that they use traps in conjunction with rodenticides. When a rat or mouse has taken some poison it is more likely to be caught in a trap and then the body can be removed and the risk of bad odours reduced.

Once the infestation is eradicated then I suggest paying attention to proofing the house to prevent further infestation. You can get more information on how to prevent rats and mice getting in on the Kiwicare website.

A drunk walks into a bar with a rat and a frog. The drunk asks the barman if he can have a free drink if he shows him something amazing. "OK" says the barman, "But it must be truly amazing."
The drunk puts the frog on the bar piano and the frog begins to play the most amazing jazz.
"Wow!" says the barman. "That WAS truly amazing. Have a drink on me."
On finishing his drink the drunk asks "Can I have another drink if I show you something even more amazing?"
"OK." Says the barman. "If it is better than before, you can drink all night."
The drunk then sets the rat on the bar. The frog starts playing the piano and the rat sings along."
"Drinks all night for you." says the barman impressed.
An agent who has watched all this comes up to the drunk and says "I pay $1,000,000 for the frog and the rat."
"No deal" says the drunk.
"OK. What about $1,000 for the singing rat?"
"Done!" says the drunk.
"Are you mad?" says the barman to the drunk when the deal is done and the agent has left.
"Relax" says the drunk. "The frog is a ventriloquist."


  1. hey, ive put poison down as i herd scratching and scuffling i knew i had a mouse in my room, last night i got home at 3.00 am was doing my usual thing put my phone on charge and the shock when i noticed the dead mouse next to my phone :-o i love animals and would never hurt one but had no choice as i dont want my bedroom to be shared by mice... so anyway was just wondering what is the likely hood of seeing them when they die as my mum said they will go to their nest to die, clearly this one did not?

    1. Hello,

      Thank you for your comment.

      Your Mum is correct that they usually become lethargic and die in their nests. But it is, as you have found out, possible for them to die in other places. It is less common for those places to be somewhere you will find the body.

  2. I hope you can help with my problem. I have lived in my home for four years. For three of the last four years, in about October, we have had an animal die somewhere in our wall? in about the same spot each time (the smell is always in the same area.) My husband tried caulking where the siding meets the concrete block. We can also see the area where something appears to be digging next to the foundation. He has also tried digging down to see if he can find the body. With no luck. We have lots of squirrels and chipmunks in our area. Why would these animals come to the same spot each fall to die? Thank you.

    1. Hello,

      This is not an uncommon problem. If there is somewhere in your house that is suitable for animals to live and nest in they will do this each year. And if they die and the conditions are the same there will be a smell each time.

      It is difficult to determine what animal might be causing the problem, but which ever it is, rodent, squirrel, chipmunk, the best prevention would be to find the way in and seal it. However, if this cannot be found the best way to prevent the smell is to improve the ventilation to the area. So when you seal places and entry points up use mesh or other material that stops the animal but does not stop the air flow.

      Trying to find the source of a smell in a building can be very difficult because it can seem to be in one place but in fact is coming from somewhere else. It is the airflow that is moving from one the other.

      I hope this is of some help.


  3. My mom put out rat poison everywhere in my apartment. Today I started smell a rotten smell in my kitchen and I thought it was the trash can so I moved the trash can out. Then I kept smelling it behind the stove. Unfortunately my mom told me that just because I smell it there does not mean that the rat has died there. So now my question is that I have two holes thats under my kitchen counter and its big enough for the rat to go in and die but not big enough for anyone to stick there hands in to remove the rat so if thats the case and it has died in there how do I get it removed out of there.

    1. Hello Tina,

      It can be very difficult to identify where precisely a dead rat is. Your Mum is correct it can smell as if it one place and and it is another. It depends on the movement of air. Smells usually only happen when it has died somewhere warm and with little ventilation.

      In your case it may require some work to open up the space under your kitchen counter and remove the carcass ,if that is where it is.

      If you cannot find it there are some neutral deodorisers that can help reduce the smell. It normally only lasts a few days.


  4. Hi I found out we had mice about 2 weeks ago due to them running around at 4 in the afternoon. (There was only 2 but small )

    I put poison down and have recently found 2 dead mice but don't know whether or not that will have stopped them and don't know how else to keep them away due to we think it's the taxi firm next door that's attracting them due to the state of their back garden

    Any advise what to do next ??

    1. Keep replenishing the rodenticide poison until no more bait is being taken. Then you should be confident you have dealt with the infestation. But you should follow up see if you can reduce the chance of mice getting in again. See here


  5. We've had a problem with rats in our loft and cavity wall for two months. They weren't taking any bait. We finally identified where they were coming from and sealed it up. We thought if we cut off their food source. The pest controller laid bait (flucuomafen) on Thursday and when we checked on Saturday it had been taken. The last two nights (Sunday and Monday) we have had frenetic scratching in the cavity wall. The controller says the poison would have worked by now or they would have died of thirst so the rats must be coming from our neighbour (we live in a semi detached). Our neighbours have had almost no problems and are keen to help us to contain the problem so I am frustrated by his attitude. What can I do now?

    1. Hi,

      The flocoumafen bait may take several days to kill the rats. Anti-coagulants are necessarily slow acting; to prevent bait shyness and for safety - should pets accidentally access bait there is time for the antidote to be given.

      I would hope that if there is still bait there for them the treatment on your side of the property should deal with the whole population. But it would be good for both you and your neighbour to co-operate and place the same baits on both properties.

      I suggest, be patient and ask your neighbour to put out some flocoumafen bait as well.

      I hope that helps.




Please feel free to ask me a question or comment on this blog.

You may find information you are looking for here.